Recursively traverse a directory tree mapping config files for Nix Home Manager

readme.org

ͳ nix eval '(let f = import ./recurseTree.nix; in f "")' | nixfmt
{
  xdg = {
    configFile = {
      "something/b/d/e" = { source = /tmp/nixtest/b/d/e; };
      "something/c" = { source = /tmp/nixtest/c; };
      "something/recurseTree.nix" = { source = /tmp/nixtest/recurseTree.nix; };
    };
  };
}

recurseTree.nix

with (import <nixpkgs> { });
let
  inherit (builtins) map readDir foldl' attrNames dirOf toString;
  inherit (lib.attrsets)
    nameValuePair filterAttrs listToAttrs mapAttrs' setAttrByPath
    recursiveUpdate;
  listRecursive = pathStr: listRecursive' { } pathStr;
  listRecursive' = acc: pathStr:
    let
      toPath = s: path + "/${s}";
      path = ./. + pathStr;
      contents = readDir path;
      dirs = filterAttrs (k: v: v == "directory") contents;
      files = filterAttrs (k: v: v == "regular") contents;
      dirs' =
        foldl' (acc: d: recursiveUpdate acc (listRecursive (pathStr + "/" + d)))
        { } (attrNames dirs);
      files' = foldl' (acc: f:
        recursiveUpdate acc (setAttrByPath [
          "xdg"
          "configFile"
          "something${pathStr}/${f}"
          "source"
        ] (toPath f))) { } (attrNames files);
    in recursiveUpdate dirs' files';
in listRecursive